Oil-refining still



l Z0 MFM/ A on. REFINING STILL INVENTOR.

. drfW//v Hrw/ea.;- BY ,fw SU/Y HERMA/V50 E ATTORNEYS.

O. E. ANDRUS ET AL Filed Oct. 29, 1927 Aug. 14, 1928.

Patented Aug. `14, 1928.

UNITED sfraTi-:s-l PATENT oFFlcE.

OBRIN E. ANDBUS AND SUNE HERHANSON, OF MILWAUKEE, WISCONSIN, ASSIGNORS"ro A. o. sllrrn conroxarro'n, or NEW Yonx.

vIMILWAIJKEE, 4WISCONSIN, CORPORATION OF Our invention Yrelatesparticularly toI stills `l and other vessels usedin the oil .refiningindustry, but it may be usede ually as -well in other types of vesselsinich the steel equipment used is subject to the corrosive action of hotliquids and gases.

`The invention resides 1n .amethod, of making such 'a still or veeland-providing it with a liner havin for its purposethe protect-ion oftheinsi e of the .vessel from corrosion and erosion Ihelinery is formedfrom sheet metal having characteristics wholly dierentfrom those of themetal of the bod of the vessel, and has a' continuous and un rokensurface in which the characteristics ofthe metal used as a liner arepreserved in their pure state Without dilution by metals ynot having theresistant properties desired.v 4 The invention resides also in such avessel provided with aI liner formed as a .thinrolled, .imperforate,sheet of corrosion reslstlngmaterial, chromium alloy, .for example,which is attached to the inside Walls ance and effect their weldedunion-does not produce any change in the initial characteristics of themet-al used as a liner for the vessel. tains a wholly new result,whereas some of the methods heretofore used in similar attempts to linevessels have produced such a disturbance of the metal of which the lineris constituted, as to lessen its desirability.

and efficiency for the purposes of our invention, by bringing some ofthe metal of the vessel -to the surface of the liner, In other Words, byour method of applying the liner by lresistance welding, the metal of-the liner is always lpreserved'in itspure state.

, body In this particular, our-method' at-- facilitate the rapidtransference of heat, and thus-contribute 'to the maintenance ofsubstantially the same temperatures in-both theoff the vessel and theliner, and the avoidance of those Wide differences in temperature'in'thestill body andl the liner,

bonds may be produced yspot Welding at frequent and contiguous' points,orb 'bondsy -ded lines, exten ing in 4 .d1vers'd1rect1ons, and so closeto each other,A

as continuous We that the unwelded areas between the welded linesarevery small.

. The methodof resistance welding which We usegin Aattacli ing the-linerto the vessel enable'sthe connectlon between` the partsto` be effectedwithout materially disturbing vor roughenin the smooth surface of theliner, so that finlshing of'such surface 'to' remove irregularities isvnot 'ordinarily required.

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A more detailed statement as to the features residing in the inventionwill be made in connection with the description. of the drawing attachedhereto, arid the novelty residing: in theinvention will be `pointed outin ythel appended claims.

In the accompanying drawing: l y Figure 1' is a longltudinal, centra-lsectional "view of `a, lined oil refining still con structedy inaccordance with our invention. Fig. A2'.1s a transverse sectlonal viewAthrough the same.

Fig. 3 isa dla-grammatic, longitudinal seol tional view through the'center of a, still,

such as "is illustrated in Figs. 1 'a-nd'2, in

d-icating one method by which the liner may be applied to the still.

In the drawing, Figs. 1 and 2, the numeral 10 indicateslthe 'hollowjbodyof anoil refill? -ing still, or vessel of similar type and purance withour invention; The curvature ogf pose,`- and the numeral' 11, a curved,thin sheet-metal. liner applied thereto, inaccordas exaggerated inproportion to Ithethicknessl of the plates forming the body ofthefstill, for the sake of clearness. f,

4'Our eforts havebeen directedr gto .the production Voi? an unbrokenliner for vessels which are subject to Aexcessive heat `lWhile in use.,The 'liner which we as@ is ,.tenistitutsd cal properties and commercialfeatures, such as will render it applicablelto oil rener lll use. Byheated vessels, we mean vesse heated externally or internally, or b heatcontained in the charging iiuld. areful analysis of experiments and pastfailures, caused us to believe that a better heat transfer between theshell or body of the vessel and the Vliner was the key to the solutionof the mechanical difficulties heretofore encountered. W'e conceived4the idea of placing resistance welded bonds, shown 1n the drawing asspots 12, between the hner 11 and the shell 10, at points suflicientlyclose to each other so that the. heat transfer 4on cooling or heating,would not set upsevere temperature differences in the two metals.

To make the liner commercially practical,-

and at the same time obtain satisfactory chemical properties, that is,to keep the chemical composition of the Tliner surface uniform orpractically uniform over the Y bondedand unbonded surface, we conceivedthe idea of resistance welding, and so avoid change in the character ofthe metal ofthe liner. There were many factors affecting the mechanical,chemical and commercial properties, so that only by trial andexperimentation could the combined efectbe determined. As a result ofthis research, we are able to produce for the first .time a satisfactorychromium alloy lined vessel, such vessel and lining being designed forsubjection to heat changes, by following the procedure hereinafteroutlined.

Sections of the shell are formed and lined, preferably before making upthe sections into a complete unit. However, it is also ssible to applythe lining after the vessel 1s partially or completely assembled. We do.

`not limit ourselves'to the production of a complete liner, but may onlypartially line the vessels, as for instance, the vapor region in acracking still. As a liner, we prefer to use thin sheets of low carbonchromium iron alloy, of approximately 14% chromium, or a. low carbon,chromium, nickel, iron alloy ofaapproximately 20% chromium and 10%nickel. However, we do not limit ourselves to any particular alloycontaining chromium,

but may use any suitable metals o r alloys thereof. We find it conduciveto the best results to use resistance welding in attaching the liner tothe shell by welding at distances of not more than six inches betweenwelded areas, as bonding at greater distances is not satisfactory. Weprefer bonding by resistance spot welding at points of about oneinchdown to continuous lines, as we have found that limitation to give themost satisfactory results with fg to 1/8 sheet alloy.

. We prefer to weld the seams at the meetngedges of the liner sheets byresistance surface of the liner.

'spot welding, but we may use other methods of resistance welding, arcwelding, or gas welding for the seams. Our method of welding the linerseams most satisfactorily, is to place a strip of chromium alloy betweenthe meeting edges of the liner, and spot weld at overlapping intervalsto produce a continuons bond of the lliner sheets along the seams. gThesurface at the seams may be ground flush after Welding, if necessary.

We may employ either of three distinct types of electrode applicationsin attaching the liner, namely, applying the electrodes from oppositesides of the work, applying both electrodes from the liner side of thework, as shown in Fig. 3, or using the work as one electrode andapplying the other electrode to the liner. We prefer to line vessels`method utilizes two electrodes, 14 yand 16,

applic-d to -the liner surface. We prefer to Weld one'spot at a timewith a transformer circuit, therefore we use a comparatively smallelectrode 16, with a comparatively large electrode 14, or group ofelectrodes.

However, we can Weld two spots at a time with a transformer circuit, inwhich case we would use electrodes 14 and 16 of the same size. Weconnect the electrodes 14 and 16 to the secondary ot' a transformer,preferably by short`leads 15 andv 17.V The electrodes 14 and 16,supported in any mobile manner, are urged by any suitable compressingmeans into engagement with the liner 11, the imposed liner thereby beingforced into an intimate cont-act with the inside wall of the body 10, soas to establish a good electrical connection therebetween. spot on theliner and an underlying area on the shell have become suitably heated byresistance to the passage of the electrical current, the pressuremovement of the electrode 16 will e'eet the welding of the metals at theheated spot. The mobile compressing means carrying the welding deviceswill then be adjusted for another welding operation at a predeterminedor other point, and the operations repeated, until the whole of theliner 11 has been spotted to the shell at contiguous points distributedover the whole The resistance spot welding operations effect noappreciable disturbance of the surface of the` liner l1, but

lV h en a will leave it in a practically smooth condition, so that onlyvery slight, if any, finishing operations will be necessary. Whateverseams may exist at the meeting edges of the thin lates used in forminthe liner will then be closed, preferably y spot welding as beforedescribed.

Corrosion of oil refinery equipment is particularly severe in'that typeof equipment used for cracking petroleum oils. Corrosion in the crackinequipment is largely due to the action of 2S gas, liberated or formedduring the cracking of sulphur bearing oils, on steel at elevatedtemperatures. The temperatures encountered in oil cracking equipment rane from 600 F. to 1000o F. It is wel known that HZS attacks iron rapidlyat temperatures above 500 F. The amount and extent of corrosion is suchthat it renders the equipment unsafe after a comparatively short periodof use, such period varying with conditions attending the use of thestill, principal among which is amount and type of sulphur occurence inthe oil. With very.corros1ve oils, it is possible for the wall thicknessof the still to become reduced as much as 11E inch per month.

Our investigations show that comparatively little has been done in thepast with regard to the prevention of corrosion in oil distilling andcracking equipment. The methods of handling corrosive oils are: First,to use thick-walled steel apparatus and allow corrosion to take place;second, to use chemical neutralizing agents; third, to constructapparatus with corrosion resisting Walls.

The present tendency is to build a wall sutiiciently thick to allowconsiderable corrosion to take place before the equipment becomesunsafe. This practice is expensive and requires frequent shut-downs forinspection and ascertainment of the wall thickness, and a continuallylowering of working pressures to conform with the decreasing wallthickness., Some refineries have at-` tempted, with some success, theuse of neutrallzing agents, applied within the still during crackingoperations, to neutralize the corrosive agents. These include suchmaterials as lime and caustic soda. Chro- 1 mium plating of relineryequipment has recently been tried, but plating large apparatus of the'present type presents consider- .able difliculties, which. from apractical standpoint, are nearly insurmountable.

`Chromium and some chromium alloys have been found to be much moreresistant to' hydrogen sulphideat high temperatures than stee i Linersinthe form of perforated sheets for vessels have been attemptedheretofore, but without success. This failure, in practically everycase, is due to severe buckling'of the liner and oftentimes breaking ofthe welded bonds, due to insufficient strength to resist the resultantstresses and distortion of the liner.

During the starting or stopping operation@y of the vessels, such forexample, as cracking stills, it has been found that the temperaturedifferences between the liner and the shell, have been so pronounced asto make impractical in use all liners heretofore attempted. Bymathematical calculation, it is made apparent that the maximum stressper unit area developed by any definite temperature difference betweenthe liner and the shell is independent of the distance between weldedareas. This has tended to discourage work on separate liners. Bymathematical calculation, it is also apparent that the stress perv unitof area, developed by any definite temperature difference between theliner and shell, is inversely roportional to the thickness of the liner,t e shell thickness remaining constant. This fact has tended to preventthe use of thin liners, because of cracking Aand warping. The greatexpense of perforating the liners and arc or gas Welding the bonds, andgrinding the inner Wall surface so as to 'free itfrom `deposits by thearc and make it smooth,l has limited attempts to line vessels in thismanner.

vArc or gas welding through perforations Vin a liner produces poorqualit-y of corrosion resisting bonds, especially in alloy liners,because of varying composition and porosity existing vat the weldedpoints. To our knowledge resistance welding of imperforate liners' hasnever been tried heretofore. Attemptshave been made atbonding theperforated liner heavily by arc Welding at a few spots and leaving theseams unwelded,

the ideal being to allow the liner to expand and contract with as fewobstructions as possible` so that fewer stresses would de-` velop.` Thismethod has not been satisfactory, mainlybecause of ,difficultiesencountered due. to materials getting between the shell and-the liner..

Ourirnperforate thin sheet liner has many features which'serve to makeit a useful and practical invention. A chromium bearing alloy liner, forexample, resists ILIZS Vcorrosion* very well at temperatures at which4steel is 'rapidly attacked, especially above 500 F. The 'liner greatlyincreases the length of life ofthe vesel in which it is used. The useoffsuchv a liner greatly simplifies inspection to ascertain itscondition,Y

as in practice it is lnecessary to drill holes 'through the still walls.and measure the wall thickness frequently to determine Whether the stillis safe for further operation at a particular pressure. With a hnedvessel such as we have produced, it inspection shows the Aliner to beintact, no drilling of the shell is necessary, for itis then known thatthe still walls possess their original thickness?v The `liner which wehave produced kis, "s mooth and not subject to warping, as ourmethodavoids the warping of liners due heretofore to unequal rates otexpansion or contraction of the liner with respect to the'shell. In anoil still, the most severe condition usually occurs during the processof cooling down, preparatory to cleaning or inspection. The liner maycoolv much more rapidly than the shell, with the tendency to contractfaster than the shell. Upon contraction, the liner has a tendency tostraighten out between welded areas, and pull away from rather thankconform to the curvature vof the shell. When the liner thus pulls lawayand its contact is broken, the heat transfer between it and the shell isgreatly reduced,resulting in an increased temperature dillerence andalso increased permanent distortion of the liner.

The liner, as we apply it, is free from this severe warping ordistortion. lVe have vbeen able to accomplish this mostly by increasingthe heat conductivity between the liner and shell to such an extent, dueto their intimate and frequent points of connection, that the two areessentially at'the same temperature.

heat developed during resistance welding is very localized. thuseliminating troubles which occur where the welding heat is lessrestricted.

By using resistance welding, the vimperforate liner will have the samechemical composition throughout, including the seams. This condition atthe seams is more dilicult to accomplish when using arc or gas welding.lVe have found in arcjor gas welding perforated chromium alloys, thatchromium is readily oxidized. and that the steel boils up through theperforations and mixes unevenly with the alloy tending to make thecorrosive resistance of the weld very low in places, and in such we havealso found it almost impossible to produce a liner without blow holesand cracks` -which cause porosity, at the welded points.

The use ot our method of resistance welding brings the cost of applyingthe liner than six inches apart, we may also form the bonds ascontinuous resistance welded lilies,

extending in divers directions, and having in any area a separation notgreater than that specified, and itis to be understood that where in theclaims we refer to points, we contemplate continuous resistance weldedlines as well as spot welded areas.

The ends ot the vessel, or parts other than of tubular formation, willbe lined inthe same nianncr'with liners specially shaped to tit suchparts.

One essential factor in our invention which enables us to achieve theresults desired, resides in the provision of a thin, imperferate, sheetliner of corrosion resisting metal or alloy, which is welded through theliner and to the shell Vor body of the vessel Without disturbing thecharacteristics of the metal constituting the liner. While we havereferred to chromium as a suitable metal, other metals and alloys havingthe necessary resistant properties, may be used for the purposes of ourinvention.

Having thus described our invention, what we claim and desire to secureby Letters Patent of the United States, is:

1.' The method of lining vessels, which 'comprises the operations ofsecuring a liner within the vessel by disposing a thin imperforate sheetof corrosion resisting alloy against the inner wall of the body of thevessel, and bondingthe said liner to the said body by electrical weldingat requent'and contiguous points through the liner without changing thenature of the liner, to thereby prevent distortion of the liner from itsposition in the vessel by temperature differences and provide for anincreased transference of heat between the liner and the body of thevessel.

-2. The method of lining vessels, which comprises the operations ofsecuring a liner within the vessel by disposing a thin imperforatecurved sheet of chromium alloy against the curved inner wall of the bodyof the vessel, and bonding the said liner to the said body by electricalresistance welding at frequent and contiguous points, to thereby preventdistortion of the liner from its posit-ion in the vessel by temperaturedifferences and provide for an increased transference of heat betweenthe liner and the body of the vessel. Y

3. The method of lining vessels, which comprises the operations ofsecuring a. liner within the vessel by disposing thin imperforate sheetsof chromium alloy against the inner wall of the body of the vessel, andbonding the said lining sheets to the said body by electrical resistancewelding at frequent and contiguous points, and welding the llt) sheetsto the body of the vessel at their meeting edges, to thereby preventdistortion of the liner from its position in the vessel by temperaturediierences and provide for an increased transference of heat between theliner and the body of the vessel.

4. The method of lininor vessels, which comprises the operationsofbsecuring a liner within the vessel by disposing thin imperioratecurved sheets of chromium alloy against the inner wall of the body ofthe vessel, and bonding the said lining sheets to the said body by spotwelding at frequent and conti nous pomts, to thereby prevent distortionof the liner from its position in the vessel by temperature differencesand rovide for an increased transference of heat tween the liner and thebody of the vessel, arranging a stri of like alloy between the meetingedges of t e sheets, and successively spot welding along the seams toform a continuous bon between abutting sheets and the bodyof the vessel.

5. The method of lining vessels, which comprises the o erations ofsecuring a liner within the vesse by pressing a thin imperiorate sheetof chromium alloyv against the inner wall of the body of the vessel tomake a .good electrical Contact, passing an electrical current throu hthe parts at the point of their contact to eat the same, applyingpressure to the said liner at the heated point to weld it to the body ofthe vessel, and reating the operations until the liner has n welded tothe body at frequent and contiguous points, to hold the liner againstdistortion from its position in the vessel by temperature differencesand provide for anincreased transference of heat from the liner l to thebody of the vessel.

6. The method -of lining vessels which comprises the o erations ofsecuring a liner within the vesse by disposing av thin imper `foratesheet of corrosion resisting alloy against the inner wall of the body ofthe vessel and bondin the said liner to the said body by spot wel ing atfrequent and contiguous points, to prevent distortion of the liner fromits position in the vessel by temperature dilerences and rovide for anincreased transference of Y eat between the liner and the body of thevessel.

7; The method of lining vessels, which comprises the operations ofsecuring a liner within the vessel by pressing a thin imperforate sheetof chromium alloy. against the inner wall of the body ofthe vessel tomake' a good electrical contact, passing an electrical ,current throughthe parts at the point of contact to heat the same to weld the liner .tothe body at the point of contact, and repeatin the operations until theliner has been -We ded tothe body at frequent and contiguous points, toprevent distortion of the liner from its position in the vessel by.temperature di'erences-and provide for an increased transference ofheat between the liner and the body of the vessel.

8. The method of lining vessels for use in.

oil refining or like purposes, which comprises the o erations ofsecuring a liner within the vesse by disposing a thin perforate sheet ofcorrosion resisting alloy against the inner wall .of the body of thevvessel, and bonding the said liner to the 'said I,body by resistancewelding at places not more than six inches apart, to thereby preventdistortion of the liner from its position in the vessel by temperaturediilerences and rovide for an increased transference of eat between theliner and the body of the vessel.

9. The method of lining vessels for use in oil refining or likepurposes, which comprises the operations of securing a liner within thevessel by disposing a thin imperforate sheet of chromium alloy againstthe inner wall of the body of the vessel, and bonding the said liner tothe said body by spot Welding at places not more than six inches apart,to thereby prevent distortion of the liner sol from its position in thevessel by temperature differences and provide for an increasedtransference lof. heat between the liner and the body of the vessel'.-

v10. A vessel for useJ in oil refining or other purposes, comprising abody or shell anda liner therefor, the said linel` being constituted ofa thin, imperforate, sheet of chromium alloy having corrosion resistingproperties, arranged in close en ement with the inside wall of the bodyo the vessel and attached thereto by resistance weld-v ing at frequentand contiguous points to thereby prevent distortion of the liner fromits position in the vessel by temperature changes and afford increasedheat transference between the lliner and the bodyffof the vessel. a

A11.y A vessel for use in oil refining or other purposes, comprising abody or shell and a liner therefor, the said liner being constituted ofthin, imperforate, sheet 'metal of corrosion resisting properties,arranged in close engagement with the inside wall of the body of thevessel and attached thereto4 by resistance'welding at frequent andcontiguous points to thereby prevent distortion of t-he liner from itsposition in the vessel by ltemperature changes and alford increased,vheat transference between the liner and the tuted ,of thin, imperforate,sheet metal corrosion resisting pro erties, arrangedfit1'l closeengagement with t e inside wall of the' `body of the vessel and attachedthereto byl spot welding at ,frequent andVVSV contiguous points tothereby prevent distortion of thel quent and contiguous points tothereby hold the liner against distortion from` its position in thevessel by temperature changes and afford increased heat transferencebetween the. liner and the body of the vessel.

14. A vessel for use in oil refining or other purposes, comprising abody or shell and .a liner therefor, the said liner being constituted ofthin, iinperforate, metal sheets of corrosion resisting properties,arranged n close engagement with the inside wall of the body of thevessel and permanently attached thereto by resistance welding at pointsclose to each other, to thereby vprevent distortion of the liner fromits fixed position in the vessel bv temperature changes and affordincreased heat transference through the welded bonds between the linerand the body of the vessel, the meeting edges of the sheets beingresistance welded to the body of the vessel on continuous lines to closethe joints and produce a liner of uniform, initial characteristics.

15. A vessel for use in oil refining or other i purposes, comprising abody or shell and a liner therefor, the said liner being constituted ofthin, imperforate, chromium alloy sheets of corrosion resistingproperties, arranged in close engagement With the inside wall of thebody of the Vessel and permanently attached thereto by resistancewelding at points close to each other to thereby prevent distortion ofthe liner from its fixed position in the vessel by temperature changesand afford increased heat transference through the welded bonds betweenthe liner and the body of the vessel, the meeting edges of the sheetsbeing resistance welded to the body of the vessel on continuous lines toclose the joints and produce a liner of uniform, initialcharacteristics.

16. A vessel for use in oil refining or other purposes, comprising abody or shell and a liner therefor, the said liner being constituted ofthin, imperforate, metal sheets of corrosion resisting properties,arranged in close engagement with the inside wall of the body of thevessel and permanently attached thereto by spot welding at points closeto each other to thereby prevent distortion of the liner from its fixedposition in the vessel by temperature changes and afford increased heattransference through the welded bonds between the liner and the body ofthe vessel, the meeting edges of the sheets being resistance Welded tothe body of the vessel on continuous lines to close the joints andproduce a liner of uniform, initial characteristics.

17. A vessel for use in oil refining or other purposes, comprising abody or shell and a liner therefor, the said liner being constituted ofthin, imperforate, chromium alloy sheets of Ycorrosion resistingproperties, arranged in close engagement with the inside `wall of thebody of the vessel and permanently attached thereto by spot Welding atpoints close to each other to thereby prevent distortion of the linerfrom its fixed position in the vessel by temperature changes and afl'ordincreased heat transference through the Welded bonds between the linerand the body of the vessel, the meeting edges of the sheets beingresistance Welded to the body of the vessel on continuous lines to closethe joints and produce a liner of uniform, initial characteristics.

In testimony whereof We have signed our names at Milwaukee, lvisconsin,this 14th day of October, 1927.

ORRIN E. ANDRUS. SUNE HERMANSON.

